Climate-driven storms add runoff to Maine lakes, degrading water quality

On a forested path from a seasonal camp down to Great Pond in Belgrade, a small but critical construction project was underway.

A trio of workers from the Youth Conservation Corps struggled to dig a shallow trench. Once they removed the stubborn roots and rocks, it was going to be lined with gravel and mulch.

The upgraded path doesn’t look like much, but looks can be deceiving, said Max Comis, a junior at the University of Maine and worker on the crew.

“The mulch and the rocks we’re going to put on top of this, it’s going to filter the water. We have further filtration below it, and it is going to stop the bad things from going into the water,” Comis said.

Human caused climate change is overheating Maine’s lakes and ponds , changing their biology and threatening their health.

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Climate change is overheating Maine’s pristine lakes

But the state’s climate future also includes fiercer rainstorms such as those in western Maine last December. Intense deluges and flooding can tear apart roads and bridges and further erode shorelines, flooding Maine lakes and ponds with nutrient pollution, according to a 2020 assessment from the Maine Climate Council .

In the face of those challenges, nonprofits and homeowners are working harder than ever to limit shoreline erosion and storm runoff.

With waters on some lakes 5.5 degrees Fahrenheit warmer than they were in the 1980s, it takes less pollution to trigger a decline in water quality, said Tristan Taber, water quality program director at Lake Stewards of Maine. The group trains volunteers to monitor water quality and collects data from lakes and ponds across the state.

“That warmer water does accelerate the increased productivity of the lake,” Taber said.

“And so if you have a big slug of phosphorus that’s getting delivered through erosion processes or fertilizers on people’s lawns that are washing off into the lake, as well as warmer water, you’re definitely going to accelerate that algae bloom likelihood,” he added.

Heavier storms add an extra set of problems.

“You know, we get these big high volume, rainfall events where there’s a lot of velocity of water moving across the landscape [and that] brings a lot more erosion, because higher velocity water means it’s picking up more material carrying it further,” Taber said.

With accumulating sources of storm runoff and phosphorus pollution, Taber and other advocates argue for finding and fixing erosion far away from the shoreline.

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People around the lake may care a lot about reducing erosion, but the lake watershed could extend miles upstream, Taber said. And if erosion and sediment runoff isn’t being handled at its upstream source, there’s only so much lakefront property owners can do to directly prevent pollution from leeching in.

“I think that this concept of large scale watershed connectivity needs to be looked at for lakes, we really need that more holistic view,” Taber said.

About an hour and a half southwest of Belgrade, Susan Gallo took a tour around a camp in Otisfield on the west shore of Thompson Lake.

Gallo, executive director of advocacy group Maine Lakes, said the responsibility for defending the state’s public great ponds is often left up to landowners.

Reinforcing shorelines and improving camps can be expensive work, and there’s very little public funding available. The federal government provides grants to repair erosion , but only on lakes and ponds already categorized with impaired water quality. There’s only a handful of such water bodies in Maine.

Gallo said there’s an unfair perception that lakefront property owners are rich enough that they don’t need help preserving a public resource.

“Imagine if you had a state park somewhere that we all could access,” she said.

“But then you told all the homeowners around it, hey, all of you, you’re responsible for the health of the state park. That would be really strange. But that’s what we have with lakes,” Gallo added.

A couple years ago when Cary Phoenix and her husband bought the camp in Otisfield, there was a broken septic holding tank and buried cesspool. Stormwater went straight down a slanted asphalt driveway.

“Gradually, you just notice that the water is just flowing into the lake, and I know some stuff about phosphorus. And that’s not great,” Phoenix said.

She got in touch with her local lake association to get certified Lake Smart . It’s a program that evaluates waterfront properties’ erosion issues and encourages measures to manage runoff.

Phoenix didn’t get a passing grade on her first certification attempt last year.

But after adding boxed gravel steps down to the water, fixing drip lines off the camp roof, adding erosion mulch and cultivating a plant buffer on the shoreline, Phoenix thinks her chances are much better this time around. She’s even volunteered to help find problems at other camps on Thompson Lake.

“I feel like because we had the opportunity to have a place on the lake that we needed to work hard to preserve it,” Phoenix said.

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Pollution threats are growing deep in Maine lakes

All the work might seem like overkill, but Gallo said that’s the point. Maine Lakes coordinates the Lake Smart program and recently toughened its standards to match the predicted intensity of future storms. With overheating lake waters, Gallo said, the threat of phosphorus pollution is greater than it used to be. Every chance to address erosion is critical.

“You have this healthy lake, but it’s gonna die from 1,000 little cuts around at [the] shoreline because every little source of phosphorus is going to add up and make a difference,” Gallo said.

If everyone applies a bandage to those cuts, Gallo added, it can help Maine lakes survive.

This article appears through a media partnership with Maine Public .